Contemporary studies of human taste perception indicate a relationship between the number of taste buds and taste sensitivity, but limited quantification of human tasted bud populations prevents an adequate assessment of the relationship between taste bud number and their normal function and dysfunction. The objective of this project is to determine an average number and distribution of fungiform taste buds in representative examples of normal (undiseased) human tongues. Their number and distribution is to be compared among populations of tongues as a function of age, sex, race or any distinguishing factors of the donor's phenotype. The initial studies will be done by histological reconstruction with light microscopy of regions of cadaver tongues obtained from the North Carolina Anatomical Board. Since the pores of taste buds react with organic dyes, the surfaces of tongues from human cadavers will be stained and photographed to resolve the location of pores by their superficial features. The same tongues which are photographed will be reconstructed by histological microscopy to confirm the locations of taste buds. Adaptation of the staining and photographic techniques developed in the study of cadaver tongues will be utilized to count taste buds on the tongues of living animals by superficial microscopic examination. Taste pores will be examined on tongues of anesthetized rabbits. Electrophysiological responses will be recorded from the chorda tympani nerves in a sample of animals to insure that the procedure is innocuous to normal taste responses. The receptor distributions obtained from living rabbits will be compared with those obtained by histological examination of the same tongues. These studies will provide a preliminary assessment of the distribution of human fungiform taste buds as well as a method for assessing taste bud numbers in living subjects. Such a method would be beneficial in the diagnosis of patients with taste dysfunction and in the study of taste perception by normal subjects.